#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<int,int,int> tt;
#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())
const ll MOD = 1e9 + 7;
const int mn = 1e5 + 5;
int add (int a, int b) {
return a + b - (a + b < MOD ? 0 : MOD);
}
int sub (int a, int b) {
return a - b + (a - b >= 0 ? 0 : MOD);
}
int mul (int a, int b) {
return 1LL * a * b % MOD;
}
int binpow (int a, int b = MOD - 2) {
int ans = 1, lg = 31 - __builtin_clz(b);
for (int i = 0; i <= lg; i++) {
if (b & (1 << i)) ans = mul(ans, a);
a = mul(a, a);
}
return ans;
}
const int half = binpow(2);
int calc (int n) {
return mul(mul(n, add(n, 1)), half);
}
int calcAll (int h, int w) {
return mul(calc(h), calc(w));
}
int calcRight (int h, int w) {
return mul(calc(h), w);
}
int dp[mn], dpRight[mn], h[mn], w[mn], pre[mn];
stack<pii> st;
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);
int n; cin >> n;
for (int i = 1; i <= n; i++) cin >> h[i];
for (int i = 1; i <= n; i++) {
cin >> w[i];
pre[i] = add(pre[i - 1], w[i]);
}
st.emplace(0, 0);
int ans = 0;
for (int i = 1; i <= n; i++) {
while (st.top().first > h[i]) st.pop();
int delWidth = sub(pre[i - 1], pre[st.top().second]);
int curRight = add(dpRight[st.top().second], calcRight(h[i], delWidth));
st.emplace(h[i], i);
dpRight[i] = add(curRight, calcRight(h[i], w[i]));
ans = add(ans, add(mul(curRight, w[i]), calcAll(h[i], w[i])));
}
cout << ans;
return 0;
}
